1. Field of the Invention
The present invention relates to a plug device for sealing a container for a liquid material, such as a thermos bottle. The plug device not only seals the opening but also facilitates dispensing of the liquid from the container.
2. Background Technology
Conventionally, a plug for a liquid container, such as a thermos bottle disclosed in a Japanese Utility Model Application, Second Publication S57 (1982)-38119 has been known. The plug body comprises an outer plug member and an inner plug member which is screwed into the outer plug member, and a ring-shaped liquid path formed between the inner plug member and the outer plug member.
In such a plug body, when the inner plug member is screwed into the outer plug member, a packing provided in the inner plug member closes the ring-shaped liquid path, and when the inner plug member is loosened, the liquid path is opened.
In the plug body of such a construction, because the closing/opening of the liquid path is performed by turning of the inner plug member against the outer plug member, closing/opening operation of the container is cumbersome. Therefore, a push-button operated plug body developed earlier by the inventors of the present invention as disclosed in a Japanese Utility Model Application, First Publication, S63(1988)-103629, has become more widely utilized.
Although the push-button type plug body disclosed in the above mentioned application is more convenient than other types, because the liquid path is disposed inside the plug body, it creates an impression of being non-hygienic since the liquid path could not be totally cleaned. Also, there was a problem that the drops of the previously dispensed liquid remained in the path. When the liquid drops are left behind, the liquid remains are exposed to the atmosphere, and could contribute to uncleanliness and quality deterioration. If the liquid residue happens to be hot, hot liquid could run out if the container was upset.